1. Field of the Invention
The present invention relates to a window made of synthetic resin, and more particularly to a synthetic resin window which is suitable for automotive vehicles or the like.
2. Description of the Related Art
A synthetic resin window for automotive vehicles is disclosed, e.g., in Japanese Utility Model Application Publication No. 61-32,808, as being manufactured by an injection molding process. The known synthetic resin window generally includes a window body member of transparent or semi-transparent synthetic resin, such as polycarbonate or acrylic resin, as well as a frame member extending along the peripheral edge of the body member and formed into a predetermined shape which corresponds to flange of a relevant vehicle body panel. Due to susceptibility of the synthetic resin to scratches or the like damages, the outer surface of the window body member is generally covered by a hard coated film layer, while the outer surface of the frame member has a paint applied thereto and is an opaque coated layer of a desired color.
In this connection, Japanese Patent Application Laid-open Publication No. 63-137,017 discloses a process wherein a resin film formed with a hard coated layer thereon is inserted into the cavity of an injection mold, and a transparent synthetic resin is subsequently injected into the cavity such that the resin film is fusion-bonded to a sheet of the injected resin obtained after it has been subjected to cooling and curing. In this case, the resin film completely covers the entire surface of the window body member. Furthermore, Japanese Patent Application Laid-open Publication Nos. 63-159,126; and 63-159,127 each discloses a process wherein a hard coated layer is formed on the surface of the window body member, and the window body member is subsequently placed into the cavity of an injection mold to integrally form the frame member along the peripheral edge of the window body member.
The abovementioned known synthetic resin window proved to be advantageous particularly in its reduced weight, but suffers from a problem of significantly low rigidity as compared with conventional inorganic glass windows. Thus, the synthetic resin window as mounted on the vehicle body panel often exhibits undesirable deformation or damage as a result of fastening force or the like. The required rigidity of the synthetic resin window might be realized either by increasing the thickness of the window body portion itself, or by providing reinforcing ribs on the frame portion. However, these solutions are not very suitable from practical viewpoints that an increased thickness of the window body portion would make it almost impossible to achieve a reduced weight of the window as a whole, while a provision for reinforcing ribs on the frame portion more or less results in formation of undesirable sink mark on the outer surface of the frame portion to significantly deteriorate the appearance.
Moreover, the hard coated layer on the window main body member tends to be readily separated due to deformation or damage as a result of insufficient rigidity of the window. Also, even when the hard coated layer is formed on a primer layer, the hard coated layer is not maintained in good adhesion with plasticized synthetic resin forming the frame member, e.g. polyvinylchloride resin or polyurethane resin, so that the frame member tends to be readily separated from the window body member. Besides, the application of paint to the frame member to form the opaque layer makes it difficult to simplify the manufacturing steps.